Ladder systems, agricultural vehicles, and related methods

ABSTRACT

A ladder system includes a first rail, a second rail parallel to the first rail, a ladder bracket supported by and configured to slide along the first rail and the second rail, a ladder coupled to the ladder bracket and configured to rotate with respect to the ladder bracket between a lowered position and a storage position, and an air spring coupling the ladder to the ladder bracket and configured to apply a force to the ladder when the ladder is in the lowered position to keep the ladder in the lowered position. Another ladder system includes a rail, a bumper stop below the rail, a ladder bracket, a ladder, a bumper, and an air spring. An agricultural vehicle includes a chassis supported by a plurality of wheels, and a ladder system carried by the chassis. Related methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the filing date of U.S.Provisional Patent Application 62/878,957, “Ladder Systems, AgriculturalVehicles, and Related Methods,” filed Jul. 26, 2019, the entiredisclosure of which is incorporated herein by reference.

FIELD

Embodiments of the present disclosure relate to ladder systems andmobile machines, such as self-propelled agricultural machines andsimilar vehicles. More particularly, embodiments relate to a mobilemachine onto which an operator may need to climb in the field to makeadjustments, repairs, or inspections.

BACKGROUND

Some agricultural vehicles are configured to be operated in fields amongrow crops. Application machines such as self-propelled sprayers, forexample, may have wheels configured to pass between crop rows and aspray boom that extends outwardly from the vehicle to spray the crops asthe machine travels through the field. In order to avoid damaging thecrops as the vehicle moves through the field, the vehicle should havesufficient ground clearance (the distance between the vehicle body andthe surface over which it moves) to clear the crops.

While a standard height agricultural vehicle may be used to processshort crops, such as early stage corn or the like, difficulties arisewhen processing taller crops, such as mature corn, that are taller thanthe ground clearance of a standard vehicle. For such crops,high-clearance vehicles may be used. While high-clearance vehiclesprovide sufficient clearance to pass over the top of taller crops, it istypically necessary for an operator or a technician to use a ladder toaccess the cab and other parts of the vehicle. The ladder isconventionally attached to the high-clearance vehicle, and may be foldedor detached when not in use. If the operator fails to fold up or detachthe ladder before moving the vehicle, the ladder, the vehicle, and/orthe field may be damaged.

BRIEF SUMMARY

In some embodiments, a ladder system includes a first rail, a secondrail parallel to the first rail, a ladder bracket supported by andconfigured to slide along the first rail and the second rail, a laddercoupled to the ladder bracket and configured to rotate with respect tothe ladder bracket between a lowered position and a storage position,and an air spring coupling the ladder to the ladder bracket andconfigured to apply a force to the ladder when the ladder is in thelowered position to keep the ladder in the lowered position.

An agricultural vehicle may include a chassis supported by a pluralityof wheels, and a ladder system carried by the chassis.

Certain embodiments include a method of moving a ladder coupled to aladder bracket configured to slide along a first rail and a second railof an agricultural vehicle. The method includes rotating the ladder withrespect to the ladder bracket to overcome a force of an air spring onthe ladder and to cause a bumper to separate from the second rail,applying an upward force from the air spring to the ladder to direct theladder toward a storage position, and transporting the agriculturalvehicle.

In other embodiments, a ladder system includes a rail, a bumper stopbelow the rail, a ladder bracket supported by and configured to slidealong the rail, a ladder coupled to the ladder bracket and configured torotate with respect to the ladder bracket between a lowered position anda storage position, a bumper coupled to the ladder, and an air springcoupling the ladder to the ladder bracket and configured to push thebumper against the bumper stop when the ladder is in the loweredposition.

Other embodiments include a method of moving a ladder coupled to aladder bracket configured to slide along a first rail and a second railof an agricultural vehicle. The method includes disengaging a retainingpin to enable the ladder to rotate with respect to the ladder bracket,rotating the ladder with respect to the ladder bracket to overcome aforce of an air spring on the ladder and to cause a bumper to separatefrom the second rail, sliding the ladder bracket along the first railand the second rail, applying an upward force from the air spring to theladder to direct the ladder toward a storage position, engaging theretaining pin to retain the ladder in the storage position, transportingthe agricultural vehicle, disengaging the retaining pin from the ladder,applying a downward force against the air spring to direct the laddertoward a lowered position, sliding the ladder bracket along the firstrail and the second rail, rotating the ladder downward with respect tothe ladder bracket to overcome a force of the air spring on the ladderand to cause the bumper to contact the second rail, and engaging theretaining pin with the ladder and the ladder bracket.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of the presentdisclosure, various features and advantages may be more readilyascertained from the following description of example embodiments of thedisclosure when read in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an agricultural vehicle in accordance with oneembodiment;

FIG. 2 illustrates a portion of the agricultural vehicle of FIG. 1including an application system;

FIG. 3 illustrates a ladder system, in a lowered position, that may beused to access parts of the application system shown in FIG. 2;

FIG. 4 illustrates the ladder system in an intermediate position;

FIG. 5 illustrates the ladder system in a storage position;

FIG. 6 is a side view of the ladder system shown in FIG. 3;

FIG. 7 is a detail view of a portion of the ladder system shown in FIG.3;

FIG. 8 illustrates a ladder system in accordance with anotherembodiment; and

FIG. 9 is a simplified flow chart illustrating a method of operating aladder system.

DETAILED DESCRIPTION

All references cited herein are incorporated herein in their entireties.If there is a conflict between definitions herein and in an incorporatedreference, the definition herein shall control.

The illustrations presented herein are not actual views of any machineor portion thereof, but are merely idealized representations that areemployed to describe example embodiments of the present disclosure.Additionally, elements common between figures may retain the samenumerical designation.

The following description provides specific details of embodiments ofthe present disclosure in order to provide a thorough descriptionthereof. However, a person of ordinary skill in the art will understandthat the embodiments of the disclosure may be practiced withoutemploying many such specific details. Indeed, the embodiments of thedisclosure may be practiced in conjunction with conventional techniquesemployed in the industry. In addition, the description provided belowdoes not include all elements to form a complete structure or assembly.Only those process acts and structures necessary to understand theembodiments of the disclosure are described in detail below. Additionalconventional acts and structures may be used. Also note, the drawingsaccompanying the application are for illustrative purposes only, and arethus not drawn to scale.

As used herein, the terms “comprising,” “including,” “containing,”“characterized by,” and grammatical equivalents thereof are inclusive oropen-ended terms that do not exclude additional, unrecited elements ormethod steps, but also include the more restrictive terms “consistingof” and “consisting essentially of” and grammatical equivalents thereof.

As used herein, the term “may” with respect to a material, structure,feature, or method act indicates that such is contemplated for use inimplementation of an embodiment of the disclosure, and such term is usedin preference to the more restrictive term “is” so as to avoid anyimplication that other, compatible materials, structures, features, andmethods usable in combination therewith should or must be excluded.

As used herein, the term “configured” refers to a size, shape, materialcomposition, and arrangement of one or more of at least one structureand at least one apparatus facilitating operation of one or more of thestructure and the apparatus in a predetermined way.

As used herein, the singular forms following “a,” “an,” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

As used herein, spatially relative terms, such as “beneath,” “below,”“lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,”“right,” and the like, may be used for ease of description to describeone element's or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. Unless otherwise specified,the spatially relative terms are intended to encompass differentorientations of the materials in addition to the orientation depicted inthe figures.

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone of ordinary skill in the art would understand that the givenparameter, property, or condition is met with a degree of variance, suchas within acceptable manufacturing tolerances. By way of example,depending on the particular parameter, property, or condition that issubstantially met, the parameter, property, or condition may be at least90.0% met, at least 95.0% met, at least 99.0% met, or even at least99.9% met.

As used herein, the term “about” used in reference to a given parameteris inclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the given parameter).

FIG. 1 illustrates an agricultural vehicle 100 depicted as vehicle forapplying liquids to a field. The agricultural vehicle 100 broadlyincludes a chassis 102, a plurality of wheels 104 or otherground-engaging elements supporting the chassis 102 above a groundsurface, an application system 200, an operator cab 106, and an enginecompartment 108, wherein an engine for driving the agricultural vehicle100 is located. A plurality of suspension modules 110 interposed betweenthe wheels 104 and the chassis 102 support the chassis 102 on the wheels104 and provide suspension, height adjustment and/or steering functions.A cab access ladder 112 is configured to enable an operator to reach theoperator cab 106.

The application system 200 is supported on the chassis 102 and may be,for example, a liquid sprayer system. A reservoir 114 is in fluidconnection with the application system 200 and is configured to containliquid to be applied to the field. The application system 200 includes apair of lateral booms 116 supporting hoses, pumps and spray nozzles orsimilar components for dispersing or otherwise applying the contents ofthe reservoir 114 to a crop (note that outer portions of the lateralbooms 116 are omitted from FIG. 1). Alternatively, the applicationsystem 200 may be configured to apply dry material to a field andtherefore may include a hopper and a mechanism for dispersingparticulate material from the hopper, such as a pneumatic spreader orone or more spinners.

The operator cab 106 is supported on the chassis 102 and is typicallypositioned forward of the application system 200. The operator cab 106presents a control environment that enables the operator to control thefunctions of the agricultural vehicle 100, including operating theapplication system 200.

FIG. 2 is a rear perspective view of an application system 200 that maybe a part of the agricultural vehicle 100 shown in FIG. 1. The lateralbooms 116 are shown in an extended position for use applying material toa field. As known in the art, the lateral booms 116 may fold inward fortransport. A platform 202 enables an operator to inspect and maintainparts of the application system 200, such as the level of material inthe reservoir 114, proper operation of the parts of the applicationsystem 200, etc. The operator may occasionally need to access theplatform 202 in the field. The operator can use an attached laddersystem 300 to climb up to the platform 202. The ladder system 300 mayalso be used to access other portions of the application system 200.

FIG. 3 illustrates the ladder system 300 and the platform 202 isolatedfrom the application system 200 for clarity. A first rail 302 and asecond rail 304 are arranged parallel to one another, and typicallyparallel to the ground under the agricultural vehicle 100. A ladderbracket 306 is supported by and configured to slide along the first rail302 and the second rail 304.

A ladder 308 is coupled to the ladder bracket 306 and configured torotate with respect to the ladder bracket 306 between a lowered position(i.e., the position shown in FIG. 3) and a storage position (shown inFIG. 5). The ladder 308 may be configured to not reach all the way tothe ground in the lowered position. Therefore, even if the operatoraccidentally moves the agricultural vehicle 100 without raising theladder 308, the ladder system 300 may not sustain any damage if it doesnot contact the ground.

The ladder 308 includes a plurality of rungs 310 arranged generally in acommon plane and a handle 312 extending from the common plane of therungs 310. The handle 312 may be used by the operator to raise and lowerthe ladder 308. A strap 314 may also be attached to the handle 312 sothat the operator can pull on the handle 312 via the strap 314 when theladder 308 is in the storage position (i.e., in case the handle 312 isout of reach of the operator).

The ladder system 300 may include an air spring 316 coupling the ladderbracket 306 to the ladder 308. The air spring 316 may apply a force tothe ladder 308 when the ladder 308 is in the lowered position to keepthe ladder 308 in the lowered position and to keep the ladder 308 fromsliding along the first rail 302 and the second rail 304. The air spring316 may apply a force to the ladder 308 when the ladder 308 is in anintermediate position, as illustrated in FIG. 4 (i.e., between thepositions shown in FIG. 3 and FIG. 5) to push the ladder 308 upward,toward the storage position (FIG. 5). Thus, the air spring 316 mayprovide multiple functions: to keep the ladder 308 down in the loweredposition when the ladder 308 is in use, to assist the operator inraising the ladder 308 to the storage position, and to keep the ladder308 in the storage position when the ladder 308 is not in use.

The ladder bracket 306 and the ladder 308 may slide laterally along therails 302, 304 when the ladder 308 is in the intermediate position(e.g., as shown in FIG. 4). Therefore, the ladder 308 may be moved toanother location along the rails 302, 304 to enable the operator toaccess different parts of the agricultural vehicle 100.

One or more fixed rungs 318 may be disposed above the first rail 302,and may be fixed with respect to the chassis 102 of the agriculturalvehicle 100. The fixed rungs 318 may assist the operator in reaching theplatform 202. One or more handrails 320 may be secured to theagricultural vehicle 100 above the first rail 302 for the safety of theoperator. Typically, and as shown in FIG. 3, a pair of handrails 320 isused. As shown in FIG. 5, the ladder 308 may be disposed between thehandrails 320 when the ladder 308 is in the storage position. The airspring 316 may prevent the ladder 308 from moving out of the storageposition on its own, but in some embodiments, the ladder 308 may befurther secured in the storage position by a hook, strap, pin, rope,latch, or other device.

FIG. 6 is a simplified side view of the ladder system 300 when theladder 308 is in the lowered position. The ladder 308 may have a bumper602 arranged such that, when the ladder 308 is in the lowered position,the bumper 602 contacts the second rail 304. In other embodiments, theladder 308 may contact the chassis 102 or another member that is fixedrelative to the chassis 102, as described in more detail below. Forexample, the bumper 602 may be adjacent one of the rungs 310 of theladder 308. The bumper 602 may include an elastomeric material oranother material to engage the second rail 304 and stabilize the ladder308 laterally, such that the ladder 308 does not slide along the firstrail 302 and the second rail 304 when the ladder 308 is down. Thus, eventhough the ladder 308 may not extend all the way to the ground, theladder 308 and ladder bracket 306 may nonetheless be stably supported bythe first rail 302 and the second rail 304.

FIG. 7 is a simplified perspective view of the ladder bracket 306 and aportion of the first rail 302, the second rail 304, and the ladder 308.

The ladder bracket 306 may include a first tubular member 702 around thefirst rail 302 and a second tubular member 704 around the second rail304. The first tubular member 702 and the second tubular member 704 maybe connected to one another by a connecting member 706, such as bywelds. In other embodiments, the ladder bracket 306 may be formed as asingle unitary member (e.g., by casting, additive manufacturing, etc.).A spring bracket 708 may be secured to the connecting member 706. Rigidconnection of the first tubular member 702 to the second tubular member704 may enable the ladder bracket 306 to slide along the first rail 302and the second rail 304 without rotating about the rails 302, 304.

The ladder bracket 306 may have greaseless bushings in contact with therails 302, 304, such that the ladder bracket 306 can slide freely alongthe rails 302, 304 when the ladder 308 is in the intermediate position(e.g., as shown in FIG. 4).

The ladder bracket 306 may include a fixed hinge element 710 having ahole through which a retaining pin 712 can pass, and the ladder 308 mayinclude a rotating hinge element 714 with a corresponding hole. When theretaining pin 712 is in place, the rotating hinge element 714 of theladder 308 is locked with respect to the fixed hinge element 710 of theladder bracket 306. The retaining pin 712 therefore prevents the ladder308 from rotating upward from the lowered position.

The ladder bracket 306 may also include a rung 716 on the first rail 302in the form of plates with rough edges or another shape that providestraction for an operator climbing the ladder system 300. Unlike therungs 310 of the ladder 308, the rung 716 does not rotate with theladder 308, but may slide along the first rail 302 with the ladder 308.

FIG. 8 is a simplified view of another embodiment of a ladder system800. The ladder system 800 is similar to the ladder system 300 shown inFIG. 3 through FIG. 7, but includes just one rail 802. A ladder bracket806 slides along the rail, and a ladder 804 swivels up and down betweena lowered position (shown in FIG. 8) and a storage position. The rail802 has a non-round shape (e.g., a square, a hexagon, a keyway in anotherwise round structure, etc.) to keep the ladder bracket 806 fromrotating around the rail 802. A bumper 810 attached to the ladder 804rests against a bumper stop 812 when the ladder 804 is in the loweredposition. The bumper stop 812 may be any surface, such as a structuralpanel or beam of the agricultural vehicle to which the ladder system 800is attached, or a part added for the specific purpose of acting as thebumper stop 812. The bumper stop 812 may be fixed relative to thechassis 102 below the rail 802. Another bumper stop 812 may be locatedbelow another part of the rail 802 such that the ladder 804 may besupported in another location along the rail 802. Either the bumper 810,the bumper stop 812, or both may include an elastomeric material or anyother material to prevent ladder 804 from sliding along the rail 802when in the lowered position. In some embodiments, the shape of thebumper 810 and the bumper stop 812 may prevent lateral movement of theladder 804 in the lowered position. For example, the bumper stop 812 maydefine a recess 814 into which the bumper 810 may extend.

FIG. 9 is a simplified flow chart illustrating a method 900 of moving aladder connected to an agricultural vehicle along a first rail, such asthe agricultural vehicle 100 shown in FIG. 1. As shown in block 902 ofFIG. 9, a retaining pin may be disengaged to enable the ladder to rotatewith respect to a ladder bracket.

In block 904, the ladder is rotated with respect to the ladder bracketto overcome a force of an air spring on the ladder and to cause a bumperto separate from a second rail.

In block 906, the ladder bracket slides along the first rail and thesecond rail. In block 908, an upward force is applied to the ladder bythe air spring to direct the ladder toward a storage position. In block910, the retaining pin is engaged to retain the ladder in the storageposition. In block 912, the agricultural vehicle is transported, such asthrough a field.

In block 914, the retaining pin is disengaged from the ladder. In block916, a downward force is applied against the air spring to direct theladder toward a lowered position. In block 918, the ladder bracketslides along the first rail and the second rail. In block 920, theladder rotates downward with respect to the ladder bracket to overcome aforce of the air spring on the ladder and to cause the bumper to contactthe second rail. In block 922, the retaining pin engages with the ladderand the ladder bracket.

The actions shown in FIG. 9 and described above need not all beperformed, and need not be performed in the order shown. Furthermore,the method 900 may be modified based on the specific elements in aladder system (e.g., to correspond to the ladder system 800 shown inFIG. 8).

Ladder systems as disclosed herein may provide a convenient means for aperson to access a platform on an agricultural vehicle via avehicle-mounted ladder. Furthermore, because the ladder need not rest onthe ground to be stable, the ladder may provide additional safety ascompared to conventional ladders. For example, the ladder may be stableeven over uneven ground, and failure to stow the ladder before movingthe agricultural vehicle may not cause damage to the ladder, theagricultural vehicle, or the field.

Though shown and described along the rear of an agricultural vehicle,the ladder systems may be used in other locations. For example, the cabaccess ladder 112 shown in FIG. 1 may also incorporate elementsdisclosed herein. The ladder systems may also be used on other vehicles,such as industrial and construction equipment or any other vehicle onwhich occasional ladder access is beneficial. Ladder systems asdisclosed may also be used in fixed applications, such as in warehouses.For example, rail(s) may be affixed to storage shelving, and a ladder asdisclosed may be configured to slide laterally along the rail(s).

Additional non-limiting example embodiments of the disclosure aredescribed below.

Embodiment 1: A ladder system comprising a rail, a ladder bracketsupported by and configured to slide along the rail, a ladder coupled tothe ladder bracket and configured to rotate with respect to the ladderbracket between a lowered position and a storage position, and an airspring coupling the ladder to the ladder bracket and configured to applya force to the ladder when the ladder is in the lowered position to keepthe ladder in the lowered position and to keep the ladder from slidingalong the rail.

Embodiment 2: The ladder system of Embodiment 1, further comprising abumper coupled to the ladder and configured to contact a member fixedrelative to the rail of the ladder system when the ladder is in thelowered position.

Embodiment 3: The ladder system of Embodiment 2, wherein the bumpercomprises an elastomeric material.

Embodiment 4: A ladder system comprising a rail, a bumper stop below therail, a ladder bracket supported by and configured to slide along therail, a ladder coupled to the ladder bracket and configured to rotatewith respect to the ladder bracket between a lowered position and astorage position, a bumper coupled to the ladder, and an air springcoupling the ladder to the ladder bracket and configured to push thebumper against the bumper stop when the ladder is in the loweredposition.

Embodiment 5: The ladder system of Embodiment 4, wherein at least one ofthe bumper and the bumper stop comprises an elastomeric material.

Embodiment 6: The ladder system of Embodiment 4 or Embodiment 5, whereinthe bumper stop defines a recess therein, and wherein the air spring isconfigured to push the bumper into the recess when the ladder is in thelowered position.

Embodiment 7: The ladder system of any one of Embodiment 1 throughEmbodiment 6, wherein the ladder is configured to rotate to anintermediate position between the lowered position and the storageposition, wherein when the ladder is in the intermediate position, theladder bracket can slide along the rail.

Embodiment 8: The ladder system of any one of Embodiment 1 throughEmbodiment 7, wherein the ladder bracket comprises at least onegreaseless bushing in contact with the rail.

Embodiment 9: The ladder system of any one of Embodiment 1 throughEmbodiment 8, further comprising a retaining pin configured to lock theladder to the ladder bracket in the lowered position.

Embodiment 10: The ladder system of any one of Embodiment 1 throughEmbodiment 9, wherein the ladder comprises a plurality of rungs arrangedgenerally in a common plane and a handle extending from the common planeof the rungs.

Embodiment 11: The ladder system of any one of Embodiment 1 throughEmbodiment 10, further comprising a strap coupled to the ladder andconfigured such that, when a tensile force is applied to the strap, thestrap pulls the ladder from the storage position.

Embodiment 12: An agricultural vehicle, comprising a chassis supportedby a plurality of wheels and the ladder system of any one of Embodiment1 through Embodiment 11 carried by the chassis.

Embodiment 13: The agricultural vehicle of Embodiment 12, wherein theladder is configured such that, in the lowered position, the ladder doesnot reach ground under the wheels of the agricultural vehicle.

Embodiment 14: The agricultural vehicle of Embodiment 12 or Embodiment13, further comprising a platform above the rail.

Embodiment 15: The agricultural vehicle of any one of Embodiment 12through Embodiment 14, further comprising at least one fixed rung abovethe rail, wherein the at least one fixed rung is fixed with respect tothe chassis of the agricultural vehicle.

Embodiment 16: The agricultural vehicle of any one of Embodiment 12through Embodiment 15, further comprising a pair of handrails above therail, wherein the ladder is disposed between the handrails when theladder is in the storage position.

Embodiment 17: The agricultural vehicle of and one of Embodiment 12through Embodiment 16, further comprising an application systemcomprising a lateral boom extending from the chassis.

Embodiment 18: A method of moving a ladder coupled to a ladder bracketconfigured to slide along a rail of an agricultural vehicle. The methodincludes rotating the ladder with respect to the ladder bracket toovercome a force of an air spring on the ladder and to cause a bumper toseparate from a point of contact with the agricultural vehicle, applyingan upward force from the air spring to the ladder to direct the laddertoward a storage position, and transporting the agricultural vehicle.

Embodiment 19: The method of Embodiment 18, further comprisingdisengaging a retaining pin to enable the ladder to rotate with respectto the ladder bracket before rotating the ladder.

Embodiment 20: The method of Embodiment 18 or Embodiment 19, furthercomprising sliding the ladder bracket along the rail.

Embodiment 21: The method of any one of Embodiment 18 through Embodiment20, further comprising engaging a retaining pin to retain the ladder inthe storage position.

Embodiment 22: The method of any one of Embodiment 18 through Embodiment21, further comprising, after transporting the agricultural vehicle,applying a downward force against the air spring to direct the laddertoward a lowered position, and rotating the ladder downward with respectto the ladder bracket to overcome a force of the air spring on theladder and to cause the bumper to contact the agricultural vehicle.

Embodiment 23: The method of any one of Embodiment 18 through Embodiment22, further comprising engaging a retaining pin with the ladder and theladder bracket to retain the ladder in the lowered position.

Embodiment 24: A method of moving a ladder coupled to a ladder bracketconfigured to slide along a first rail and a second rail of anagricultural vehicle. The method includes disengaging a retaining pin toenable the ladder to rotate with respect to the ladder bracket, rotatingthe ladder with respect to the ladder bracket to overcome a force of anair spring on the ladder and to cause a bumper to separate from thesecond rail, sliding the ladder bracket along the first rail and thesecond rail, applying an upward force from the air spring to the ladderto direct the ladder toward a storage position, engaging the retainingpin to retain the ladder in the storage position, transporting theagricultural vehicle, disengaging the retaining pin from the ladder,applying a downward force against the air spring to direct the laddertoward a lowered position, sliding the ladder bracket along the firstrail and the second rail, rotating the ladder downward with respect tothe ladder bracket to overcome a force of the air spring on the ladderand to cause the bumper to contact the second rail, and engaging theretaining pin with the ladder and the ladder bracket.

While the present disclosure has been described herein with respect tocertain illustrated embodiments, those of ordinary skill in the art willrecognize and appreciate that it is not so limited. Rather, manyadditions, deletions, and modifications to the illustrated embodimentsmay be made without departing from the scope of the disclosure ashereinafter claimed, including legal equivalents thereof. In addition,features from one embodiment may be combined with features of anotherembodiment while still being encompassed within the scope ascontemplated by the inventors. Further, embodiments of the disclosurehave utility with different and various vehicle types andconfigurations.

What is claimed is:
 1. A ladder system, comprising: a rail; a ladderbracket supported by and configured to slide along the rail; a laddercoupled to the ladder bracket and configured to rotate with respect tothe ladder bracket between a lowered position and a storage position;and an air spring coupling the ladder to the ladder bracket andconfigured to apply a force to the ladder when the ladder is in thelowered position to keep the ladder in the lowered position and to keepthe ladder from sliding along the rail.
 2. The ladder system of claim 1,wherein the ladder is configured to rotate to an intermediate positionbetween the lowered position and the storage position, wherein when theladder is in the intermediate position, the ladder bracket can slidealong the rail.
 3. The ladder system of claim 1, wherein the ladderbracket comprises at least one greaseless bushing in contact with therail.
 4. The ladder system of claim 1, further comprising a retainingpin configured to lock the ladder to the ladder bracket in the loweredposition.
 5. The ladder system of claim 1, wherein the ladder comprisesa plurality of rungs arranged generally in a common plane and a handleextending from the common plane of the rungs.
 6. The ladder system ofclaim 1, further comprising a second rail parallel to the rail.
 7. Theladder system of claim 1, further comprising a bumper coupled to theladder and a bumper stop below the rail, wherein the air spring isconfigured to push the bumper against the bumper stop when the ladder isin the lowered position.
 8. The ladder system of claim 7, wherein atleast one of the bumper and the bumper stop comprises an elastomericmaterial.
 9. An agricultural vehicle, comprising: a chassis supported bya plurality of wheels; and a ladder system carried by the chassis, theladder system comprising: a rail fixed with respect to the chassis; aladder bracket supported by and configured to slide along the rail; aladder coupled to the ladder bracket and configured to rotate withrespect to the ladder bracket between a lowered position and a storageposition; and an air spring coupling the ladder to the ladder bracketand configured to apply a force to the ladder when the ladder is in thelowered position to keep the ladder in the lowered position and to keepthe ladder from sliding along the rail.
 10. The agricultural vehicle ofclaim 9, wherein the ladder is configured such that, in the loweredposition, the ladder does not reach ground under the wheels of theagricultural vehicle.
 11. The agricultural vehicle of claim 9, furthercomprising a platform above the rail.
 12. The agricultural vehicle ofclaim 9, further comprising at least one fixed rung above the rail,wherein the at least one fixed rung is fixed with respect to the chassisof the agricultural vehicle.
 13. The agricultural vehicle of claim 9,further comprising a pair of handrails above the rail, wherein theladder is disposed between the handrails when the ladder is in thestorage position.
 14. The agricultural vehicle of claim 9, furthercomprising an application system comprising a lateral boom extendingfrom the chassis.
 15. The agricultural vehicle of claim 9, furthercomprising a bumper coupled to the ladder and configured to contact amember that is fixed relative to the chassis when the ladder is in thelowered position.
 16. A method of moving a ladder coupled to a ladderbracket configured to slide along a rail of an agricultural vehicle, themethod comprising: rotating the ladder with respect to the ladderbracket to overcome a force of an air spring on the ladder and to causea bumper to separate from a point of contact with the agriculturalvehicle; applying an upward force from the air spring to the ladder todirect the ladder toward a storage position; and transporting theagricultural vehicle.
 17. The method of claim 16, further comprisingdisengaging a retaining pin to enable the ladder to rotate with respectto the ladder bracket before rotating the ladder.
 18. The method ofclaim 16, further comprising sliding the ladder bracket along the rail.19. The method of claim 16, further comprising engaging a retaining pinto retain the ladder in the storage position.
 20. The method of claim16, further comprising, after transporting the agricultural vehicle:applying a downward force against the air spring to direct the laddertoward a lowered position; and rotating the ladder downward with respectto the ladder bracket to overcome a force of the air spring on theladder and to cause the bumper to contact the agricultural vehicle.